There are two ways to control automobile headlamps of the prior art: one is for halogen headlamps and the other is for high intensity gas discharge headlamps. The halogen headlamps directly use the voltage transmitted from the power supply of an automobile to control the illumination of the halogen lamps. Further, two lateral sides of a car are each installed with a motor for moving a corresponding halogen lamp, whereby the halogen lamp can be either a far light or a near light. Due to a lack of a voltage regulator, the voltage applied to the halogen lamps is unstable, directly influencing the lifespan of the lamps and probably causing illumination instability. The high intensity gas discharge headlamps are argon-filled light bulbs respectively installed on the two lateral sides of an automobile, each powered by the power supply of an automobile through a voltage regulator. The regulator also determines whether to cut down the voltage. Since that the power supply of an automobile supplies the voltage needed for the far lights and the near lights and that the voltage is stabilized by a voltage regulator within a control box, the supplied voltage can be maintained at a constant level and its noises can be limited, whereby, as the light is switched between near lights and far lights, the illumination quality of the multi-functional high intensity discharge automobile headlamp of the prior art will be better. However, since the argon-filled light bulbs are powered by the power supply of an automobile, the low voltage has an unstable value in voltage, leading to a problem of floating voltage (6V or 8V) and therefore intensity instability of the near lights powered by the low voltage. The problem will shorten the life of the bulbs.